


Archimedes and Stoplights

by heartbreaknow



Category: Marvel Cinematic Universe, Spider-Man (Tom Holland Movies)
Genre: Established Relationship, Ficlet, Fluff, M/M, Peter Has a Hair Trigger, Peter is At Least 18, They Are Both Very Smart and Love Science, and a little smut, and each other, they get each other
Language: English
Status: Completed
Published: 2020-03-14
Updated: 2020-03-14
Packaged: 2021-02-28 22:08:24
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,149
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23144443
Author URL: https://archiveofourown.org/users/heartbreaknow/pseuds/heartbreaknow
Summary: The first time Tony stops in the middle of sex to write down a potential breakthrough he’s just had on a tricky lab problem, he and Peter have been together for about six months.
Relationships: Peter Parker/Tony Stark
Comments: 36
Kudos: 332





	Archimedes and Stoplights

**Author's Note:**

  * For [LearnedFoot](https://archiveofourown.org/users/LearnedFoot/gifts).



> Peter and Tony stopping in the middle of sex when scientific inspiration strikes is entirely LearnedFoot's idea. The specifics of what that might look like, as seen in this fic, are my own.

The first time Tony stops in the middle of sex to write down a potential breakthrough he’s just had on a tricky lab problem, he and Peter have been together for about six months.

These ill-timed flashes of inspiration are not uncommon. Something about the specific state of exertion and euphoria brought about by fucking Peter senseless seems particularly conducive to sudden conceptual breakthroughs. It’s perfect, in a sense—two of his favorite occupations, brought together into one. But it’s an ironically flawed kind of perfection, because whatever idea he has while Peter is writhing underneath him isn’t always still there by the time they’ve both collapsed limply on the bed, limbs draped over each other.

Generally he just accepts the potential loss and keeps going. It’s what he always did with Pepper, because it wasn’t always easy for her to get there, and he wasn’t about to rob her of a hard-earned orgasm by stopping when she was halfway. But Peter…Peter once accidentally came after three minutes of close-bodied slow dancing to a Shania Twain song. Tony’s pretty sure stopping in the middle of sex will set him back approximately not at all.

So when, after five months together, Tony has a breakthrough on a particularly tenacious problem with the nanites—and that breakthrough happens to coincide with Peter whining loudly into Tony’s shoulder and tightening around him in long pulses—Tony passionately fucks him through it…and then slows to a stop and gently pulls out.

It generally takes about thirty seconds for Peter to truly come back online after an orgasm of that calibre. So Tony murmurs a contrite, “Sorry, kid; you can yell at me for this in a minute,” and quickly reaches for the Starkpad on the nightstand.

About forty seconds later Peter mumbles a fairly lucid-sounding, “Hey,” and shifts up onto his elbow, leaning into Tony’s side. Tony feels him studying the screen of the Starkpad, and feels a bit like a dog caught licking its balls.

“I realize this probably doesn’t look great,” he says, guiltily, “but it’ll only take a second for me to jot this down, and then I won’t be distracted, and I can promise you, I will—”

“Is this for the compression problem with the nanites?” Peter interrupts, sounding…not overly hurt or upset.

Tony grunts a confirmation. “Finally realized the collapsed mass redistribution in the Mark Sixty isn’t functioning at full capacity ‘cause I haven’t been factoring in the…” he falters, stops. He looks at Peter—at his sweaty curls and his dark, keen eyes—and gives his head a twitch of a shake. “Actually, you know what, I don’t need to do this right now, I’ll just—”

“No!” Peter blurts quickly, grabbing his forearm to stop him from turning off the Starkpad. “This looks like it’s gonna work, and if you don’t write it down you might forget it. That’s always what happens to me.”

So—okay. _That’s_ new information.

“Sorry, just to clarify: you have ideas like this? While we’re having sex?” Tony asks, trying to sound casual.

Peter’s gaze shifts away, a little furtively. “Um, yeah? I mean, not—not all the time. But, sometimes.” He looks so earnest and sincere, worrying his lip a little—still flushed from orgasm.

Tony reaches his hand around Peter’s neck, cups him by the nape, and guides their mouths together.

Peter makes a muffled _mmph_ sound, and then relaxes into the kiss, and Tony tries to kiss him with the specific brand of fervent certainty Peter makes him feel more and more these days—warm and aching. He hasn’t finished noting down his idea about the nanites yet, but that’s okay. That’s fine. The feeling that he _can_ , that he doesn’t have to just ignore it until later, is a revelation. But right now he’d much rather lay here and mesh their mouths together, firm and thorough. 

When the kiss begins to get away from them, he breaks it off, but stays close, leaning their foreheads together. “What do you say we make a deal?” he says hoarsely. “In the interest of scientific progress.”

They call it the Eureka Clause. Well, Tony calls it the Eureka Clause. Peter calls it ‘purple.’

“You know, like the stoplight system? Except instead of red or yellow, this is purple, which is like, ‘I love what you’re doing and would legitimately beg you not to stop, except I just suddenly had an idea for how to prove the existence of a 19th quantum field, or like, make a microwave that perfectly heats up Hot Pockets or something, so can we please pause this for a second while I write it down?’” 

“Kid, I could make a microwave that perfectly heats up Hot Pockets any day of the week.”

Peter is laying on his back beside Tony. He raises his brows, grinning. “Could you though?” he says coyly, looking up at the ceiling. “I think you’re underestimating what a revelation in microwave technology that would be.”

Truthfully, Tony’s not sure he’s ever actually had a Hot Pocket. But he’s not going to say that; Peter would be scandalized. He’ll make the kid his ultimate microwave; Peter will see. 

It’s about five minutes before the Starkpad is back on the nightstand and Peter is in his lap again, breathing a litany of little gasps as Tony thrusts up into him. “God, you’re so… _fuck_ ,” he groans and presses deep, just as Peter bears down on him, swiveling his hips. 

The image of Archimedes flashes through his mind: springing from the bath, euphoric with epiphany. _Eureka_!

He feels that way all the time, these days. ( _I’ve found it._ )

Peter smears his panting mouth against Tony’s cheekbone, a kiss, and contracts deliberately around him, in the way he knows makes Tony want to grab him and take, and take, and _take_. There’s no scientific breakthroughs here, but he watches Peter tremble, his eyes screwed shut in pleasure, and thinks, _Fuck yeah; eureka._

He can’t say it, because it’s stupid and wouldn’t make any sense. But he can say that other thing. The thing he said months ago, accidentally, terrifyingly soon, but still doesn’t say nearly often enough.

“Love you, kid,” he pants, practically kissing it into the side of Peter’s head, his chaotic hair. “God, I love you.” And just like that, Peter comes. Comes like a dream, like a force of nature—simply because Tony told him the truest, most obvious thing inside himself. 

“Loveyou, loveyou, loveyou,” Peter sobs back, like a frantic echo, his body contracting around Tony, trying to pull him over the edge, too. 

And Peter’s stoplight thing from earlier must still be stuck in his head, because just as his thrusts get jerky and desperate and he begins to lose it, he thinks, _Green. Green._

The way this feels, six months in—every stoplight for miles and miles, green.


End file.
